1. Field of the Invention
The invention relates to traction devices. More particularly, the invention provides a traction plate adapted especially for use when the driving wheels of a motor vehicle become embedded in soft or slippery materials, such as snow, mud or sand. The device includes gripping means on both sides in order to enable the wheel to grip the traction device, and at the same time to provide a secure gripping surface on the traction device against the soft material, such as mud, sand or snow, in which the wheel is embedded.
2. Disclosure Statement
In U.S. Pat. No. 3,096,939, issued July 9, 1963 to Kalfen, a traction plate is disclosed for use in snow, mud or ice to afford traction to the wheel of a vehicle, where the plate has rectangular projections or tongues facing outwardly. However, the projections are presented perpendicularly, and accordingly do not offer sufficient traction to be useful for many possible road and weather conditions, and the projections of Kalfen do not extend completely across the width of the device, thereby obviating a strengthening function and reducing the effectiveness of the projections in gripping both the wheel and the soft surface. In U.S. Pat. No. 1,344,238, patented July 22, 1920 by William Lavallee, an articulated safety driver is disclosed for helping to lift a rear wheel embedded in sand, where the device has spurs extending downwardly into the sand, and has transverse ribs on which the wheel rides.
Other patents which may be pertinent to the field of invention include the following:
______________________________________ 1,335,546 C.J. Bardon March 30, 1920 1,339,612 J.W. Wilkins May 11, 1920 2,496,119 F. Cesen Jan. 31, 1950 2,619,289 H. Plante Nov. 25, 1952 ______________________________________
All of the disclosures of the patents enumerated above suffer the disadvantage of relatively poor traction when an attempt is made to use the devices to remove a vehicle wheel embedded in a soft material, inasmuch as none discloses ribbing angled to grip the wheel on the upper side and similarly angled to embed from the lower side of the device in the soft material.